Design and Experimental Verification of SP-Type Resonant Wireless Power Transfer System Capable for Bidirectional Power Transmission

This study proposes a new design for a wireless power transmission system. We introduce the theory of nontight coupled transformers and investigate a method for designing the parameters of an SP-type wireless power transfer (WPT) system.Using the design method, we fabricate a WPT experimental system combining a series-parallel resonant circuit and a dual active bridge (DAB)-type DC/DC converter. The fabricated system was able to transmit power with high efficiency. The system also achieved bi-directional power transmission, which is an advantage of DAB-type DC/DC converters. Power transmission was stable even when the coupling coefficient varied, demonstrating the practicality of the proposed theory and system.